Do you experience a sudden onset of insomnia at about this time every year? Not much is written on seasonal insomnia that occurs in warm weather. Yet I’m convinced it’s a real phenomenon since my posts on summer insomnia get lots of traffic starting in May.
Here’s updated information—and speculation—on what could be causing the problem and how to get a better night’s sleep.
Excessive Heat and Light
Late spring and summer are the hottest, lightest times of the year, and excessive heat and light are not very conducive to sleep.
In humans, core body temperature fluctuates by about 1.5 degrees Fahrenheit every day. Sleep is most likely to occur when core body temperature is falling (at night) and at its low point (some two hours before you typically wake up). Some research suggests that impaired thermoregulation may be a factor in insomnia, that sometimes you may simply be too hot to fall asleep. If so, a bedroom that’s too hot may exacerbate that problem, interfering with your body’s ability to cool down.
Light, too, can interfere with sleep. It does so by blocking secretion of melatonin, a hormone typically secreted at night. Exposure to bright light late in the evening or early in the morning—a phenomenon more likely to occur in months around the summer solstice—may keep you from sleeping as long as you’d like.
Other Possible Challenges to Sleep in the Summer
Swedish researchers have found that people with environmental intolerances to things like noise and pungent chemicals are more prone to insomnia than people without these intolerances. Depending on where you live, sleeping with open windows in the warm weather—if it leads to more noise or bad odors in the bedroom—could interfere with sleep.
Finally, new research conducted at Poznan University of Medical Sciences found that medical students in Poland had higher levels of circulating cortisol—a stress hormone—in the summer than in the winter. This is a preliminary result, and whether it can be confirmed or will hold true for the general population is unknown. Yet if humans do have higher levels of cortisol in the summer than in the winter, this, too, could have a negative effect on sleep.
Sleep Better in the Hot Weather
Climate control is the answer to many environmental triggers of insomnia in the spring and summer. Yet not everyone has air conditioning. If at night you’re too hot to sleep, take care to cool your sleeping quarters down in advance:
- In the daytime, keep window shades and curtains closed to block out heat from the sun.
- Later in the evening, use a window fan (facing outward) to draw cool air through the house. Open and close windows strategically so the bedroom is cool by the time you’re ready to sleep.
- If your bedroom is on an upper floor that simply won’t cool down, sleep on a makeshift bed downstairs.
If keeping windows open at night exposes you to too much outside noise, block it out with silicone ear plugs or high-tech ear plugs, or mask it with white or pink noise using a small fan, a white noise machine, or SleepPhones.
Manage Your Exposure to Sunlight
Daily exposure to bright light helps keep sleep regular—but not if the exposure comes early in the morning or at night. Sunlight that awakens you at 5 a.m. or keeps you up past your normal bedtime may shorten your summer nights, depriving you of the full amount of sleep you need. If you’re sensitive to light,
- Install light-blocking shades, curtains, and skylight covers on bedroom windows.
- Purchase a lightweight eye mask for use during sleep.
- Wear sunglasses if you’re outside in the evening.
- At home, lower shades and curtains by 8:30 or 9 p.m. even if it’s still light outside, and start your bedtime routine at the same time as you do in other seasons.
- Avoid devices with a screens in the hour leading up to bedtime.
If circulating stress hormones are an issue during the summertime (or if for any reason you’re feeling stress), then kicking back and relaxing, typical in the summer, is not necessarily going to be a dependable path to sound sleep. To reduce stress and sleep better, find a way to make regular aerobic exercise part of your day despite the heat:
- Do the outdoor sport of your choice—walking, jogging, bicycling—early in the morning or early in the evening. Mall-walking may not be very sexy, but it sure beats walking in 100-degree heat.
- Buy a seasonal membership in a gym or recreation center, where you can work out in air conditioning.
- Take up swimming.
A woman recently wrote me wondering if the allergies she normally experiences late in April could trigger seasonal insomnia. I couldn’t find any information on this. But insomnia that routinely occurs at certain times of year is probably triggered by environmental or situational factors. Figuring out what the triggers are is the first step to finding a remedy.